This invention relates to multilayer composites having at least one metal layer and at least one layer of thermoplastic organic polymer and to articles formed therefrom.
Metallized plastic articles prepared by applying a metal to a plastic material vacuum deposition, electrolytic or electroless deposition, foil lamination or similar metallizing techniques are well known. Such articles are widely employed for decorative purposes, particularly the metallized films which are quite flexible and can be shaped to some extent to conform to various contours.
Unfortunately, the degree to which such conventional metallized films or sheets or other articles can be shaped without rupture and/or separation of the metal from the polymer (herein referred to as delamination) is generally limited to those shaping procedures involving minimal dimensional changes. Even more unfortunate is the tendency of such metallized films or sheets which have been overcoated with plastic film to delaminate upon exposure to moisture and the like. As a result of such delamination, the metal layer is usually quickly destroyed upon continued exposure to the wet environment.
The tendency of the aforementioned metallized composites to delaminate upon exposure to moisture severely limits their use in many exterior applications such as bumpers, grills and other exterior brightwork in motor vehicles such as automobiles. In addition, the tendency of such metallized components to rupture upon forming or shaping into parts limits the use of such composites somewhat in barrier packaging and electrical applications as well as in the manufacture of other articles in which the composite undergoes biaxial extension to an area which is more than 50 percent greater than the original area of the composite.
In view of the aforementioned needs for useful multilayer metal/polymer composites and the deficiencies of existing metallized polymer composites, it would be highly desirable to provide a multilayer, metal/organic polymer composite that resists delamination upon exposure to moisture and exhibits excellent specular reflectance, electroconductivity and barrier to vapor transmission after substantial dimensional change.